Viscoelastic Optimization and Thermoreversible Analysis of Water Based TiO2 Sol-Gels for Efficient Photocatalytic Coatings

Water-based TiO2 sol-gel routes are attractive for sustainable photocatalytic coatings, but temperature-driven rheological drift can compromise dip-coating reproducibility and gas-phase performance. Aqueous TTIP-acetic acid sols were tuned via controlled thermal incubation (50 ℃) and cold storage (4 ℃) and characterized by vibro-viscometry and DLS microrheology with Au probes. Incubation improved the condensation to an optimal viscoelastic transition, enabling uniform nano-crystalline anatase coatings with high catalyst loading and markedly improved formaldehyde conversion under UV-A irradiation. Cold storage partially reversed aggregation and reduced loading, leading to lower conversion. In conclusion, thermoreversible control provides stable and high-performance water-based TiO2 coatings for indoor air purification.